Electric burglar-alarm



(No Model.)

- 0. At HELMAN.

ELECTRIC BURGLAR ALARM.

No. 280g47'2. Patented July 3, 1883.

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UNITED STATES PATENT OEEICE.

ORLANDO A. IIELMAN,

OF CINCINNATI, OHIO.

ELECTRIC BURGLAR-ALARIVI.

SPECIFICATION forming part of Letters Patent No. 280,472, dated July 3, 1883.

Application iiled April 7,1883. (No model.)

To all whom it may concern.-

Be it known that I, ORLANDO A. HELMAN, of Cincinnati, Hamilton county, Ohio, have invented a neW and useful Improvement in Electric Burglar-Alarms, of which the following is a specification.

In the accompanying drawings, Figure l is a diagrammatic representation of a burglaralarm embodying my invention. Fig..2 is a side elevation of the trigger device, part of the housing-Wall being removed and the trigger discharged.

A may represent the jamb, and B the adjacent part, of a door.

C is a housing for a spring-bolt, G, such as used in percussion burglar-alarms. From the upper extremity of this bolt there projects au arm, D, by which, after closure of the door, the bolt can be forcibly elevated and partially rotated, so as to rest upon ledge E of the housing.

F is a contact-piece, which, in the discharged condition of the bolt G, istouched by the latter, so as to close the circuit of a voltaic battery, H, and of aconnected electromagnetic alarm, I, of any customary or suitable construction.

It Will be seen that, When discharged, the arm D, being confined by the Walls oi" the housing C, operates as abar to the door, which prevents the opening of the same until the 30 bolt has been again retracted and turned clear out of said confining-Walls.

It is also apparent that this device may be used to operate an annunciator, so as to indi cate What particular door has been tampered 35 With.

I claim as new and of vmy invention- The burglar-alarm attachment for doors, consisting of spring-bolt Cr, having arm D, housing C, havinglug E, contact-piece F, to receive 4o the impact of the bolt when the latter is discharged, battery H, and electro magnetic v alarm I, substantially as and for the purpose set forth.

III testimony of which invention I hereunto 45 set Iny hand.

ORLANDO A. HELMAN.

Attest:

GEO. H. KNIGHT, `S. S. CARPENTER. 

